Fixed a error induced by the merge: creditsdisplay did not have an update function

squirrelbattle/display/creditsdisplay.py

@@ -16,6 +16,9 @@ class CreditsDisplay(Display):
         self.pad = self.newpad(1, 1)
         self.ascii_art_displayed = False
 
+    def update(self, game: Game) -> None:
+        return 
+
     def display(self) -> None:
         self.box.refresh(self.y, self.x, self.height, self.width)
         self.box.display()